Light guide plate and light source module

ABSTRACT

A light guide plate and a light source module are described. The light guide plate includes a main body, first stripe microstructures and second stripe microstructures. The main body includes a light incidence surface, a light-emitting surface and a light reflective surface opposite to the light-emitting surface. The light incidence surface is connected between the light-emitting surface and the light reflective surface. The light-emitting surface includes a first microstructure region and a second microstructure region arranged sequentially, and the first microstructure region is near the light incidence surface. The first stripe microstructures are disposed in the first microstructure region and extending along a direction from one side near the light-incident surface to the other side away from the light-incident surface. The second stripe microstructures are disposed in the second microstructure region along the direction. A gradient of each second stripe microstructure is gradually varied along the direction.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part application of U.S.application Ser. No. 13/761,166, filed on Jan. 28, 2013, which claimspriority to Taiwan Application Serial Number 101109144, filed Mar. 16,2012, and Taiwan Application Serial Number 101212386, filed Jun. 27,2012. This application also claims priority to Taiwan Application SerialNumber 101109144, filed Mar. 16, 2012, Taiwan Application Serial Number101212386, filed Jun. 27, 2012, and Taiwan Application Serial Number102129835, filed Aug. 20, 2013. The entire disclosures of all the aboveapplications are hereby incorporated by reference herein.

BACKGROUND

1. Field of Invention

The present invention relates to a light guide element, and moreparticularly to a light guide plate and a light source module.

2. Description of Related Art

As the rapid development of point light sources, such as light-emittingdiodes (LEDs), a light source type of backlight modules is graduallychanged from a linear light source type to a point light source type,for example from conventional linear cold-cathode fluorescent lamps(CCFLs) to point light-emitting diodes. Refer to FIG. 1 and FIG. 2. FIG.1 and FIG. 2 respectively illustrate a top view of an arrangement of alight guide plate and light-emitting diodes and a side view of aconventional backlight module. A backlight module 100 mainly includes alight guide plate 102, a plurality of light-emitting diodes 108 and acover 112.

In the backlight module 100, the light-emitting diodes 108 are disposednear a light incidence surface 106 of the light guide plate and emitlight 110 toward the light incidence surface 106 of the light guideplate 102. The cover 112 covers the light-emitting diodes 108 and aportion of a light-emitting surface 104 on a light incidence side of thelight guide plate 102, i.e. covers a non-visible region 118 of thelight-emitting surface 104. Light 110 emitted by the light-emittingdiodes 108 enters the light guide plate 102 through the light incidencesurface 106, and is emitted out of the light guide plate 102 through thelight-emitting surface 104 of the light guide plate 102 after beingguided by the light guide plate 102.

Refer to FIG. 3. FIG. 3 illustrates a side view of another conventionalbacklight module. A structure of a backlight module 100 a issubstantially the same as that of the aforementioned backlight module100, and a difference between the two structures is that a light guideplate 102 a of the backlight module 100 a includes a tapered portion 120and a flat plate portion 122. A thickness of the tapered portion 120 isgradually lessened from the light incidence surface 106 toward the flatplate portion 122. In the backlight module 100 a, expect for a top edgeof the light incidence surface 106, distances between the light-emittingsurface 104 a of the light guide plate 102 a and the cover 112 increase.

However, as shown in FIG. 2 and FIG. 3, if a covering range of the cover112 is too short, an appearance light leakage phenomenon is very easy toform in the non-visible region 118 on the light incidence side of thebacklight module 100 or 100 a. In addition, the light-emitting diodes108 are highly directional, so that an uneven brightness condition dueto the light leakage in the non-visible region 118 of the backlightmodule 100 or 100 a is very serious. Accordingly, eyes 114 of a user seethat the backlight module 100 or 100 a has poor appearance brightnessuniformity and hot spots 116 usually formed on its light incidence side,such as shown in FIG. 4. Therefore, appearance brightness distributionof the conventional backlight modules 100 and 100 a is uneven toseriously affect vision effects of the backlight modules 100 and 100 a.

SUMMARY

Therefore, one aspect of the present invention is to provide a lightguide plate and a light source module, in which a first microstructureregion of a light-emitting surface of the light guide plate near a lightincidence surface is set with various first stripe microstructures,which extend along a direction from one side of the main body near thelight-incident surface to the other side of the main body away from thelight-incident surface. The first stripe microstructures can scatterincident light of a non-visible region, so that leakage light on thenon-visible region can be effectively blurred to greatly improve anuneven brightness phenomenon in the non-visible region.

Another aspect of the present invention is to provide a light guideplate and a light source module, in which a second microstructure regionof the light-emitting surface of the light guide plate following thefirst microstructure region is set with various second stripemicrostructures. Optical trends and degrees of light concentration ofthe light guide plate can be changed by varying shapes, angles, heights,depths or arrangements of second stripe microstructures, therebyincreasing luminance value and luminance uniformity of the light guideplate and the light source module.

Still another aspect of the present invention is to provide a lightsource module, which has emitted light of highly uniform.

According to the aforementioned aspects, the present invention providesa light guide plate. The light guide plate includes a main body, aplurality of first stripe microstructures and a plurality of secondstripe microstructures. The main body includes a light incidencesurface, a light-emitting surface and a light reflective surface, inwhich the light-emitting surface is opposite to the light reflectivesurface, the light incidence surface is connected between thelight-emitting surface and the light reflective surface, and thelight-emitting surface includes a first microstructure region and asecond microstructure region arranged in sequence, and the firstmicrostructure region is nearer the light incidence surface than thesecond microstructure region. The first stripe microstructures aredisposed in the first microstructure region and extending along adirection from one side of the main body near the light-incident surfaceto the other side of the main body away from the light-incident surface.The second stripe microstructures are disposed in the secondmicrostructure region along the direction, in which a gradient of eachof the second stripe microstructures is gradually varied along thedirection.

According to a preferred embodiment of the present invention, the lightguide plate further includes a plurality of microstructures disposed onthe light incidence surface.

According to another preferred embodiment of the present invention, across-sectional profile of each of the microstructures or each of thefirst stripe microstructures is in a V-shape, an inverted V-shape or anarc-shape.

According to still another preferred embodiment of the presentinvention,

According to yet another preferred embodiment of the present invention,each of the microstructures is a convex portion or a concave portion.

According to further another preferred embodiment of the presentinvention, the light-emitting surface further includes a blank regionbetween the first microstructure region and the light-incidence surface.

According to still yet another preferred embodiment of the presentinvention, the main body includes a tapered portion and a flat plateportion. The tapered portion has a first end and a second end oppositeto each other, and a thickness of the first end is larger than athickness of the second end. The flat plate portion extends from thesecond end along the direction, and a thickness of the flat plateportion is equal to the thickness of the second end.

According to still further another preferred embodiment of the presentinvention, the first stripe microstructures are disposed on the flatplate portion.

According to yet further another preferred embodiment of the presentinvention, the light-emitting surface further includes a blank regionbetween the first microstructure region and the microstructures, and theblank region is located on the tapered portion or on both of the taperedportion and the flat plate portion.

According to yet further another preferred embodiment of the presentinvention, the first stripe microstructures are closely adjacent to eachother.

According to yet further another preferred embodiment of the presentinvention, the first stripe microstructures are separated from eachother.

According to yet further another preferred embodiment of the presentinvention, each of the first stripe microstructures is a convex portionor a concave portion.

According to yet further another preferred embodiment of the presentinvention, each of the second stripe microstructures is a convex portionor a concave portion.

According to yet further another preferred embodiment of the presentinvention, when each of the second stripe microstructures is the convexportion, the gradient of each of the second stripe microstructuresincludes a height of each of the second stripe microstructures, and theheight of each of the second stripe microstructures becomes graduallygreater from the light incidence surface along the direction. When eachof the second stripe microstructures is the concave portion, thegradient of each of the second stripe microstructures includes a depthof each of the second stripe microstructures, and the depth of each ofthe second stripe microstructures becomes gradually greater from thelight incidence surface along the direction.

According to yet further another preferred embodiment of the presentinvention, the gradient of each of the second stripe microstructuresfurther includes a width of each of the second stripe microstructures,and width of each of the second stripe microstructures becomes graduallygreater from the light incidence surface along the direction.

According to yet further another preferred embodiment of the presentinvention, when each of the second stripe microstructures is the convexportion, the gradient of each of the second stripe microstructuresincludes a height of each of the second stripe microstructures, and theheight of each of the second stripe microstructures becomes graduallysmaller from the light incidence surface along the direction. When eachof the second stripe microstructures is the concave portion, thegradient of each of the second stripe microstructures includes a depthof each of the second stripe microstructures, and the depth of each ofthe second stripe microstructures becomes gradually smaller from thelight incidence surface along the direction.

According to yet further another preferred embodiment of the presentinvention, the gradient of each of the second stripe microstructuresfurther includes a width of each of the second stripe microstructures,and width of each of the second stripe microstructures becomes graduallysmaller from the light incidence surface along the direction.

According to yet further another preferred embodiment of the presentinvention, a cross-sectional profile of each of the second stripemicrostructures is in a V-shape, an inverted V-shape, an arc-shape or atrapezoid-shape.

According to the aforementioned aspects, the present invention furtherprovides a light source module. The light source module includes a lightguide plate as descried above and a plurality of light sources adjacentto the light incidence surface of the light guide plate.

According to a preferred embodiment of the present invention, the lightguide plate further includes a plurality of microstructures disposed onthe light incidence surface.

According to another preferred embodiment of the present invention, eachof the second stripe microstructures is a convex portion or a concaveportion. When each of the second stripe microstructures is the convexportion, the gradient of each of the second stripe microstructuresincludes a height and a width of each of the second stripemicrostructures, and the height and the width of each of the secondstripe microstructures become gradually greater from the light incidencesurface along the direction. When each of the second stripemicrostructures is the concave portion, the gradient of each of thesecond stripe microstructures includes a depth and the width of each ofthe second stripe microstructures, and the depth and the width of eachof the second stripe microstructures become gradually greater from thelight incidence surface along the direction.

According to still another preferred embodiment of the presentinvention, each of the second stripe microstructures is a convex portionor a concave portion. When each of the second stripe microstructures isthe convex portion, the gradient of each of the second stripemicrostructures includes a height and a width of each of the secondstripe microstructures, and the height and the width of each of thesecond stripe microstructures become gradually smaller from the lightincidence surface along the direction. When each of the second stripemicrostructures is the concave portion, the gradient of each of thesecond stripe microstructures includes a depth and the width of each ofthe second stripe microstructures, and the depth and the width of eachof the second stripe microstructures become gradually smaller from thelight incidence surface along the direction.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing aspects and many of the attendant advantages of thisinvention are more readily appreciated as the same become betterunderstood by reference to the following detailed description, whentaken in conjunction with the accompanying drawings, wherein:

FIG. 1 illustrates a top view of an arrangement of a light guide plateand light-emitting diodes of a conventional backlight module;

FIG. 2 illustrates a side view of the conventional backlight module;

FIG. 3 illustrates a side view of another conventional backlight module;

FIG. 4 is a diagram showing appearance brightness distribution on alight incidence side of a conventional backlight module;

FIG. 5 illustrates a perspective view of a backlight module inaccordance with an embodiment of the present invention;

FIG. 5A is a cross-sectional view taken along a line AA′ of the lightguide plate of FIG. 5 in accordance with an embodiment of the presentinvention;

FIG. 5B is a cross-sectional view taken along a line AA′ of the lightguide plate of FIG. 5 in accordance with another embodiment of thepresent invention;

FIG. 6A illustrates a perspective view of a backlight module inaccordance with another embodiment of the present invention;

FIG. 6B illustrates a perspective view of a backlight module inaccordance with still another embodiment of the present invention;

FIG. 6C illustrates a perspective view of a backlight module inaccordance with yet another embodiment of the present invention;

FIG. 7A is a diagram showing appearance brightness distribution on alight incidence side of the backlight module shown in FIG. 3;

FIG. 7B is a diagram showing appearance brightness distribution on alight incidence side of the backlight module shown in FIG. 6A;

FIG. 8 is a diagram showing appearance brightness distribution curves onthe incidence sides of the backlight modules shown in FIG. 7A and FIG.7B;

FIG. 9 illustrates a perspective view of a backlight module inaccordance with further another embodiment of the present invention;

FIG. 10 illustrates a perspective view of a backlight module inaccordance with still yet another embodiment of the present invention;

FIG. 11 illustrates a perspective view of a light source module inaccordance with another embodiment of the present invention;

FIG. 11A illustrates a perspective view of a light source module inaccordance with another embodiment of the present invention;

FIG. 11B illustrates a perspective view of a light source module inaccordance with another embodiment of the present invention;

FIG. 12 illustrates a perspective view of a light source module inaccordance with another embodiment of the present invention;

FIG. 13 illustrates a perspective view of a light source module inaccordance with another embodiment of the present invention;

FIG. 14 illustrates a perspective view of a light source module inaccordance with another embodiment of the present invention; and

FIG. 15 illustrates a perspective view of a light source module inaccordance with another embodiment of the present invention.

DETAILED DESCRIPTION

Refer to FIG. 5. FIG. 5 illustrates a perspective view of a backlightmodule in accordance with an embodiment of the present invention. In thepresent embodiment, a backlight module 200 mainly includes a light guideplate 206 and a plurality of light sources 218. The light guide plate206 includes a main body 202 and a plurality of stripe microstructures204. In one exemplary example, the main body 202 may be a flat platewith a uniform thickness. The main body 202 may include a lightincidence surface 208, a light-emitting surface 210 and a lightreflective surface 212. In the main body 202, the light-emitting surface210 and the light reflective surface 212 are on two opposite sides ofthe main body 202, and the light incidence surface 208 is connectedbetween the light-emitting surface 210 and the light reflective surface212. The light incidence surface 208 of the main body 202 may be amirror surface or a surface having microstructures. In addition, thelight-emitting surface 210 of the main body 202 may include amicrostructure region 222 adjacent to the light incidence surface 208.

In the light guide plate 206, the stripe microstructures 204 aredisposed in the microstructure region 222 of the light-emitting surface210 of the main body 202. In one exemplary example, as shown in FIG. 5,the stripe microstructures 204 are arranged in the entire microstructureregion 222 of the light-emitting surface 210. In one example, the stripemicrostructures 204 are closely adjacent to each other. However, inanother exemplary example, the stripe microstructures 204 arranged inthe entire microstructure region 222 are not distributed in the entiremicrostructure region 222. An extending direction of each stripemicrostructure 204 in the microstructure region 222 is parallel to anormal line of the light incidence surface 208. In one exemplaryexample, a range of the microstructure region 222 of the light-emittingsurface 210 is within 20 mm extending from one end of the light-emittingsurface, which is connected with the light incidence surface 208, alongthe normal line of the light incidence surface 208.

In some exemplary examples, the stripe microstructures 204 may be, forexample, a plurality of V-cut structures as shown in FIG. 5A and/or aplurality of R-cut structures as shown in FIG. 5B. Referring to FIG. 5Bagain, Central angles φ of the stripe microstructures 204 composed ofthe R-cut structures may range from 60 degrees to 120 degrees, forexample. In addition, referring to FIG. 5A again, flare angles θ of thestripe microstructures 204 composed of the V-cut structures may rangefrom 60 degrees to 120 degrees, for example. In one preferred example,the central angles φ of the stripe microstructures 204 composed of theR-cut structures or the flare angles θ of the stripe microstructures 204composed of the V-cut structures are 100 degrees.

Refer to FIG. 5 again. The light sources 218 are disposed at a side ofthe light incidence surface 208, and adjacent to the light incidencesurface 208. Light-emitting surfaces 220 of the light sources 218 arepreferably opposite to the light incidence surface 208 of the lightguide plate 206, so that the light sources 218 can emit light toward thelight incidence surface 208. In one exemplary example, the light sources218 may be point light sources, such as light-emitting diodes. Theemitting light of the point light sources, such as the light-emittingdiodes, is highly directional and narrow, and by arranging the stripemicrostructures 204 within the microstructure region 222 of thelight-emitting surface 210, the light emitted from the microstructureregion 222 of the light-emitting surface 210 of the main body 202 can bescattered. Therefore, the leakage light on the light incidence side ofthe light guide plate 206 is uniformed to further uniform brightness ofa light-emitting surface of the backlight module 200.

In some exemplary examples, the light guide plate 206 may furtherselectively include a plurality of microstructures 214 according tooptical performance required by the backlight module 200. As shown inFIG. 5, the microstructures 214 may be arranged on the light reflectivesurface 212 of the main body 202 of the light guide plate 206. Themicrostructures 214 may be stripe structures, such as V-cut structuresand R-cut structures, or may be taper structures or taper indentations.

The main body of the light guide plate of the present invention may notbe a flat plate with a uniform thickness. Refer to FIG. 6A. FIG. 6Aillustrates a perspective view of a backlight module in accordance withanother embodiment of the present invention. A structure of a backlightmodule 200 a of the present embodiment is substantially the same as thatof the backlight module 200 of the aforementioned embodiment, and adifference between the two structures is that a main body 202 a of alight guide plate 206 a of the backlight module 200 a is not a flatplate with a uniform thickness.

In the backlight module 200 a, the light guide plate 206 a includes atapered portion 226 and a flat plate portion 224. The tapered portion226 has a first end 228 and a second end 230 opposite to each other. Thethickness of the tapered portion 226 is gradually decreased from thefirst end 228 to the second end 230, i.e. the first end 228 of thetapered portion 226 is thicker than the second end 230. In addition, theflat plate portion 224 extends from the second end 230 of the taperedportion 226 along the normal line of the light incidence surface 208. Athickness of the flat plate portion 224 is the same as that of thesecond end 230 of the tapered portion 226. In the present embodiment,the microstructure region 222 extends on the tapered portion 226 and aportion of the flat plate portion 224, and the stripe microstructures204 a are disposed in the microstructure region 222 on the taperedportion 226 and the flat plate portion 224.

The stripe microstructures of the present invention may not bedistributed in the entire microstructure region. Refer to FIG. 6B andFIG. 6C. FIG. 6B and FIG. 6C respectively illustrate perspective viewsof backlight modules in accordance with another two embodiments of thepresent invention. Structures of backlight modules 200 b and 200 c aresubstantially the same as that of the backlight module 200 a of theaforementioned embodiment, and differences among the structures of thebacklight module 200 a, 200 b and 200 c are that: stripe microstructures204 b of a light guide plate 206 b of the backlight module 200 b and thestripe microstructures 204 c of a light guide plate 206 c of thebacklight module 200 c are arranged in a portion of microstructureregions 222 respectively.

As shown in FIG. 6B, in the backlight module 200 b, the stripemicrostructures 204 b of the light guide plate 206 b only extend in themicrostructure region 222 on the tapered portion 226 of the main body202 a. On the other hand, as shown in FIG. 6C, in the backlight module200 c, the stripe microstructures 204 c of the light guide plate 206 conly extend in the microstructure region 222 on the flat plate portion224 of the main body 202 a.

In the present invention, the microstructure region of thelight-emitting surface of the main body of the light guide plate may bedivided into several regions, and the regions may be set with stripemicrostructures with different structure shapes, such as R-cutstructures and V-cut structures. Or, the regions of the microstructureregion may be set with stripe microstructures with a same structureshape but different central angles or flare angles. Certainly, themicrostructure region of the light-emitting surface of the main body ofthe light guide plate may be set with stripe microstructures with a samestructure shape and a same central angle or a same flare angle.

Refer to FIG. 7A, FIG. 7B and FIG. 8. FIG. 7A, FIG. 7B and FIG. 8 arediagrams respectively showing appearance brightness distribution on alight incidence side of the backlight module shown in FIG. 3, appearancebrightness distribution on a light incidence side of the backlightmodule shown in FIG. 6A, and appearance brightness distribution curveson the incidence sides of the backlight modules shown in FIG. 7A andFIG. 7B. According to FIG. 7A, it is known that the uneven brightnesscondition of the non-visible region 118 on the light incidence side ofthe conventional backlight module 100 a is very serious, and the hotspots 116 a are formed on the non-visible region 118. However, accordingto FIG. 7B, it is known that by arranging the stripe microstructures 204a parallel to the normal line of the light incidence surface 208 withinthe microstructure region 222 of the light-emitting surface 210 of thelight guide plate 206 a, the incident light of the non-visible regioncan be scattered, thereby can effectively blur the leakage light on thenon-visible region. Accordingly, the brightness distribution of themicrostructure region 222 of the backlight module 200 a is obviouslymore uniform than that of the conventional backlight module 100 a.

In addition, as shown in FIG. 8, according to the brightnessdistribution curves of the backlight modules 100 a and 200 a obtainedalong measure lines 236 in FIG. 7A and FIG. 7B, it is known that abrightness distribution curve 238 of the backlight module 200 a isgentler, and the undulation of a brightness distribution curve 240 ofthe backlight module 100 a is greater. It is also known that thebrightness distribution of the microstructure region 222 of thebacklight module 200 a is more uniform than that of the conventionalbacklight module 100 a.

Refer to FIG. 9. FIG. 9 illustrates a perspective view of a backlightmodule in accordance with further another embodiment of the presentinvention. A structure of a backlight module 200 d of the presentembodiment is substantially the same as that of the backlight module 200of the aforementioned embodiment, and differences between the twostructures are that a main body 202 b of a light guide plate 206 d ofthe backlight module 200 d includes a plurality of dot microstructures204 d rather than stripe microstructures 204; a microstructure region222 of a light-emitting surface 210 of the main body 202 b is separatedfrom the light incidence surface 208 by a distance 232; and thebacklight module 200 d further includes a cover 216.

In the backlight module 200 d, the main body 202 b includes a first sidesurface 242 and a second side surface 244 opposite to each other. Thefirst side surface 242, the light incidence surface 208 and the secondside surface 244 are connected to three adjacent edges of thelight-emitting surface 210 in sequence, i.e. the light incidence surface208 is located between the first side surface 242 and the second sidesurface 244. In addition, the first side surface 242, the lightincidence surface 208 and the second side surface 244 all are connectedbetween the light-emitting surface 210 and the light reflective surface212.

In the main body 202 b, the microstructure region 222 extends from anedge of the light-emitting surface 210 connected with the first sidesurface 242 to another edge of the light-emitting surface 210 connectedwith the second side surface 244. In one exemplary example, a direction234 of the microstructure region 222 extending on the light emittingsurface 210 from the first side surface 242 to the second side surface244 may be perpendicular to the normal line of the light incidencesurface 208. Furthermore, in one exemplary example, the distance 232between the microstructure region 222 and the light incidence surface208 may be greater than 0, and equal to or smaller than 20 mm forexample.

In the light guide plate 206 d, the dot microstructures 204 d areuniformly distributed in the whole microstructure region 222 of thelight-emitting surface 210. In addition, the dot microstructures 204 dmay be dot diffusing structures with matted surfaces and not conoidsurface structures. In some exemplary examples, the dot microstructures204 d may be sand blasting dot structures or laser dot structures formedby a sand blasting method or a laser method.

As shown in FIG. 9, the cover 216 may extend from the top of the lightsources 218 to the top of the light-emitting surface 210 of the mainbody 202 b of the light guide plate 206 d, and may at least cover thelight-emitting surface 220 of the light sources 218, the light incidencesurface 208 of the main body 202 b, and a portion of the light-emittingsurface 210 near the light incidence surface 208. In one exemplaryexample, the cover 216 may cover a portion of the microstructure region222. The cover 216 may have a reflection capability, and light emittedby the light sources 218 toward the cover 216 can be reflected to thelight-emitting surface 210 of the main body 202 b.

The emitting light of the point light sources, such as thelight-emitting diodes, is highly directional and narrow, and bydistributing the dot microstructures 204 d in the whole microstructureregion 222 of the light-emitting surface 210 of the main body 202 b, thelight reflected by the cover 216 toward the light-emitting surface 210can be scattered. Therefore, a spray phenomenon caused by the pointlight sources with high directionality can be effectively blurred by thedot microstructures 204 d. Accordingly, brightness on a light incidenceside of the light guide plate 206 d is uniformed to further uniformbrightness of a light-emitting surface of the backlight module 200 d.

Refer to FIG. 10. FIG. 10 illustrates a perspective view of a backlightmodule in accordance with still yet another embodiment of the presentinvention. A structure of a backlight module 200 e of the presentembodiment is substantially the same as that of the backlight module 200d of the aforementioned embodiment, and a difference between the twostructures is that a main body 202 a of a light guide plate 206 e of thebacklight module 200 e is not a flat plate with a uniform thickness.

In the backlight module 200 e, the light guide plate 206 e is similar tothe light guide plate 206 a shown in FIG. 6A, and includes a taperedportion 226 and a flat plate portion 224. The tapered portion 226 has afirst end 228 and a second end 230 opposite to each other. The thicknessof the tapered portion 226 is gradually decreased from the first end 228to the second end 230, i.e. the first end 228 of the tapered portion 226is thicker than the second end 230. In addition, the flat plate portion224 extends from the second end 230 of the tapered portion 226 along thenormal line of the light incidence surface 208. A thickness of the flatplate portion 224 is the same as that of the second end 230 of thetapered portion 226. In the present embodiment, the microstructureregion 222 is located on the flat plate portion 224 and does not extendto the tapered portion 226.

FIG. 11 illustrates a perspective view of a light source module inaccordance with another embodiment of the present invention. As shown inFIG. 11, a light source module 300 a mainly includes a light guide plate302 a and various light sources 304. The light guide plate 302 aincludes a main body 308 a, various first stripe microstructures 310 aand various second stripe microstructures 312 a. The main body 308 a mayinclude a light incidence surface 318, a light-emitting surface 320 anda light reflective surface 322. In the main body 308 a, thelight-emitting surface 320 and the light reflective surface 322 are ontwo opposite sides of the main body 308 a, and the light incidencesurface 318 is connected between the light-emitting surface 320 and thelight reflective surface 322. The light incidence surface 318 of themain body 308 a may be a mirror surface or a surface havingmicrostructures 332 a as shown in FIG. 11. In addition, thelight-emitting surface 320 of the main body 308 a may include a firstmicrostructure region 324 and a second microstructure region 326. Thefirst microstructure region 324 and the second microstructure region 326are arranged in sequence, in which the first microstructure region 324is nearer the light incidence surface 318 than the second microstructureregion 326.

In the light guide plate 302 a, the first stripe microstructures 310 aare disposed in the first microstructure region 324 of thelight-emitting surface 320. The first stripe microstructures 310 aextends along a direction 328, which is from one side of the main body308 a near the light-incident surface 318 to the other side of the mainbody 308 a away from the light-incident surface 318. In one exemplaryexample, an extending direction of each first stripe microstructures 310a is parallel to a normal line of the light incidence surface 318. Insome examples, the first stripe microstructures 310 a are continuouslydisposed, i.e. the first stripe microstructures 310 a are closelyadjacent to each other. In certain examples, as shown in FIG. 11A, in amain body 308 a′ of a light guide plate 302 a′ of a light source module300 a′, various first stripe microstructures 310 a′ are discontinuouslydisposed, i.e. the first stripe microstructures 310 a′ are separatedfrom each other.

Each of the first stripe microstructures 310 a may be a convex portionor a concave portion. In exemplary examples, as shown in FIG. 11, eachfirst stripe microstructure 310 a is a concave portion. In someexamples, each first stripe microstructure 310 a is a V-cut structure ora R-cut structure, i.e. a cross-sectional profile of each first stripemicrostructure 310 a is in a V-shape, an inverted V-shape or anarc-shape.

With the arrangement of the first stripe microstructures 310 a in thefirst microstructure region 324 of the light-emitting surface 320 of thelight guide plate 302 a, the leakage light on the non-visible regionnear the light-incident surface 318 is improved.

In the light guide plate 302 a, the second stripe microstructures 312 aare disposed in the second microstructure region 326 of thelight-emitting surface 320. The second, stripe microstructures 312 aextends along the direction 328 similarly. In some examples, the secondstripe microstructures 312 a are continuously disposed, i.e. the secondstripe microstructures 312 a are closely adjacent to each other. Incertain examples, the second stripe microstructures 312 a arediscontinuously disposed, i.e. the second stripe microstructures 312 aare separated from each other such as second stripe microstructures 312b shown in FIG. 12. In some examples, every two adjacent second stripemicrostructures 312 a may have an equal or unequal distances, thearrangement density of the second stripe microstructures 312 a can bechanged by adjusting the distance between every two adjacent secondstripe microstructures 312 a, thereby increasing light-guiding functionof the light guide plate 302 a.

Each second stripe microstructure 312 a may be a convex portion or aconcave portion. In exemplary examples, as shown in FIG. 11, each secondstripe microstructure 312 a is a convex portion. In some examples, eachsecond stripe microstructure 312 a is in a V-shape, an inverted V-shape,an arc-shape or a trapezoid-shape. For example, as shown in FIG. 11,each second stripe microstructure 312 a is in a trapezoid-shape.

Furthermore, a gradient of each second stripe microstructure 312 a isgradually varied along the direction 328. As shown in FIG. 11, in theexample of the second stripe microstructure 312 a being a convexstructure, the gradient of each second stripe microstructure 312 a maybe a height H or a width W. In certain examples, the gradient of eachsecond stripe microstructure 312 a may include both the height H and thewidth W. However, in the example of the second stripe microstructurebeing a concave structure, the gradient of each second stripemicrostructure may be a depth or a width. In certain examples, thegradient of each second stripe microstructure may include both the depthand the width. In an exemplary example, as shown in FIG. 11, each secondstripe microstructure 312 a is a convex portion, the gradient of eachsecond stripe microstructure 312 a includes the height H and the widthW, and the height H and the width W of each second stripe microstructure312 a becomes gradually greater from the light incidence surface 318along the direction 328. In some examples, each second stripemicrostructure 312 a is a convex portion, the gradient of each secondstripe microstructure 312 a includes the height H, and the height H ofeach second stripe microstructure 312 a becomes gradually greater fromthe light incidence surface 318 along the direction 328 while the widthW of each second stripe microstructure 312 a is constant. In certainexamples, each second stripe microstructure 312 a is a convex portion,the gradient of each second stripe microstructure 312 a includes thewidth W, and the width W of each second stripe microstructure 312 abecomes gradually greater from the light incidence surface 318 along thedirection 328 while the height H of each second stripe microstructure312 a is constant.

Optical trends and degrees of light concentration of the light guideplate 302 a can be changed by varying shapes, angles, heights, depths orarrangements of the second stripe microstructures 312 a. Thus, with thearrangement of the second stripe microstructures 312 a in the secondmicrostructure region 326 of the light-emitting surface 320 of the lightguide plate 302 a, sparser portions of the second stripe microstructures312 a, which are nearer the first microstructure region 324, can solvethe problem of the bright bands of the light guide plate 302 a andimprove the light-uniformity, and denser portions of the second stripemicrostructures 312 a, which are farther from the first microstructureregion 324, can increase brightness of the light guide plate 302 a.

In some examples, the light guide plate 302 a may further includevarious microstructures 332 a, and the microstructures 332 a aredisposed on the light incidence surface 318. Each microstructure 332 amay be a stripe structure, such as a V-cut structure or a R-cutstructure, i.e. a cross-sectional profile of each microstructure 332 ais in a V-shape, an inverted V-shape or an arc-shape. In certainexamples, each microstructure 332 a extends along a directionperpendicular to the normal line of the light incidence surface 318. Insome examples, the microstructures 332 a are continuously disposed, i.e.the microstructures 332 a are closely adjacent to each other. In certainexamples, as shown in FIG. 11B, in a main body 308 a″ of a light guideplate 302 a″ of a light source module 300 a″, various microstructures332 a′ are discontinuously disposed, i.e. the microstructures 332 a areseparated from each other.

In some examples, the light-emitting surface 320 may further include ablank region 330 between the first microstructure region 324 and themicrostructures 332 a, i.e. the first stripe microstructures 310 a donot extend from the light incidence surface 318. In certain examples,the first stripe microstructures 310 a extend from the light incidencesurface 318, and there is no blank region between the microstructures332 a and the first stripe microstructures 310 a such as the stripemicrostructures 204 b which are extending from the light incidencesurface 208 as shown in FIG. 6B.

Each of the microstructures 332 a may be a convex portion or a concaveportion. In exemplary examples, as shown in FIG. 11, each microstructure332 a is a convex portion. In some examples, each microstructure 332 ais a V-cut structure or a R-cut structure, i.e. a cross-sectionalprofile of each microstructure 332 a is in a V-shape, an invertedV-shape or an arc-shape.

With the arrangement of the microstructures 332 a on the light incidencesurface 318 of the light guide plate 302 a, the incident light can befirstly scattered. Accordingly, the uniformity of the brightnessdistribution of the region near of the light incidence surface 318 isobviously improved and hot spots can be eliminated. The blank region 330between the first microstructure region 324 and the microstructures 332a can reflect internally the light transmitted in the light guide plate302 a by no cut or dot surface such as the blank region 330, thus theproblem of the leakage light will be solved. Even few of light is notreflected in the light guide plate 302 a to become leakage, with thearrangement of the first stripe microstructures 310 a in the firstmicrostructure region 324 of the light-emitting surface 320 of the lightguide plate 302 a, the leakage light on the non-visible region will beimproved further.

The light sources 304 are disposed on a circuit board 306 and areelectrically to the circuit board 306. The light sources 304 aredisposed at a side of the light incidence surface 318, and adjacent tothe light incidence surface 318, so that the light sources 304 can emitlight toward the light incidence surface 318. In one exemplary example,the light sources 304 may be point light sources, such as light-emittingdiodes.

FIG. 12 illustrates a perspective view of a light source module inaccordance with another embodiment of the present invention. As shown inFIG. 12, a structure of a light source module 300 b of the presentembodiment is substantially the same as that of the light source module300 a of the aforementioned embodiment, and differences between the twostructures are that first stripe microstructures 310 b of a main body308 b of a light guide plate 302 b are convex portions, second stripemicrostructures 312 b of the main body 308 b are concave portions, andmicrostructures 332 b of the main body 308 b are concave portions.

In the embodiment, each first stripe microstructure 310 b is a V-cutstructure, i.e. a cross-sectional profile of each first stripemicrostructure 310 b is in an inverted V-shape. Each microstructure 332b is a V-cut structure, i.e. a cross-sectional profile of eachmicrostructure 332 b is in a V-shape. In addition, each second stripemicrostructure 312 b is in a trapezoid-shape. A gradient of each secondstripe microstructure 312 b is gradually varied along the direction 328.As shown in FIG. 12, the gradient of each second stripe microstructure312 b may be a depth D or a width W. In certain examples, the gradientof each second stripe microstructure 312 b may include both the depth Dand the width W. In an exemplary example, as shown in FIG. 12, eachsecond stripe microstructure 312 b is a concave portion, the gradient ofeach second stripe microstructure 312 b includes the depth D and thewidth W, and the depth D and the width W of each second stripemicrostructure 312 b becomes gradually greater from the light incidencesurface 318 along the direction 328. In some examples, each secondstripe microstructure 312 b is a concave portion, the gradient of eachsecond stripe microstructure 312 b includes the depth D, and the depth Dof each second stripe microstructure 312 b becomes gradually greaterfrom the light incidence surface 318 along the direction 328 while thewidth W of each second stripe microstructure 312 b is constant. Incertain examples, each second stripe microstructure 312 b is a concaveportion, the gradient of each second stripe microstructure 312 bincludes the width W, and the width W of each second stripemicrostructure 312 b becomes gradually greater from the light incidencesurface 318 along the direction 328 while the depth D of each secondstripe microstructure 312 b is constant.

FIG. 13 illustrates a perspective view of a light source module inaccordance with another embodiment of the present invention. As shown inFIG. 13, a structure of a light source module 300 c of the presentembodiment is substantially the same as that of the light source module300 a of the aforementioned embodiment, and differences between the twostructures are that first stripe microstructures 310 c of a main body308 c of a light guide plate 302 c of the light source module 300 c arein an arc-shape, second stripe microstructures 312 c of the main body308 c are in an arc-shape, and microstructures 332 c of the main body308 c are concave portions and in an arc-shape.

In the embodiment, each first stripe microstructure 310 c is a R-cutstructure, i.e. a cross-sectional profile of each first stripemicrostructure 310 c is in an arc-shape. Each microstructure 332 c is aR-cut structure, i.e. a cross-sectional profile of each microstructure332 c is in an arc-shape. Furthermore, each second stripe microstructure312 c is in an arc-shape. A gradient of each second stripemicrostructure 312 c is gradually varied along the direction 328. Asshown in FIG. 13, the gradient of each second stripe microstructure 312c may be a height H or a width W. In certain examples, the gradient ofeach second stripe microstructure 312 c may include both the height Hand the width W. In an exemplary example, referring to FIG. 13 again,each second stripe microstructure 312 c is a convex portion, thegradient of each second stripe microstructure 312 c includes the heightH and the width W, and the height H and the width W of each secondstripe microstructure 312 c becomes gradually greater from the lightincidence surface 318 along the direction 328.

FIG. 14 illustrates a perspective view of a light source module inaccordance with another embodiment of the present invention. As shown inFIG. 14, a structure of a light source module 300 d of the presentembodiment is substantially the same as that of the light source module300 c of the aforementioned embodiment, and differences between the twostructures are that first stripe microstructures 310 d of a main body308 d of a light guide plate 302 d are convex portions, microstructures332 d of the main body 308 d are convex portions, and a variation of agradient of each second stripe microstructure 312 d is different fromthat of the gradient of each second stripe microstructure 312 c.

In the embodiment, as shown in FIG. 14, the gradient of each secondstripe microstructure 312 d may be a height H or a width W. In certainexamples, the gradient of each second stripe microstructure 312 d mayinclude both the height H and the width W. In an exemplary example,referring to FIG. 14 again, each second stripe microstructure 312 d is aconvex portion, the gradient of each second stripe microstructure 312 dincludes the height H and the width W, and the height H and the width Wof each second stripe microstructure 312 d becomes gradually smallerfrom the light incidence surface 318 along the direction 328.

FIG. 15 illustrates a perspective view of a light source module inaccordance with another embodiment of the present invention. As shown inFIG. 15, a structure of a light source module 300 e of the presentembodiment is substantially the same as that of the light source module300 c of the aforementioned embodiment, and differences between the twostructures are that a main body 308 e of a light guide plate >302 e ofthe light source module 300 e is similar to the main body 202 a shown inFIG. 6A and includes a tapered portion 314 and a flat plate portion 316directly connected to each other, second stripe microstructures 312 e ofthe main body 308 e are concave portions, and microstructures 332 e ofthe main body 308 e are convex portions.

In the embodiment, as shown in FIG. 15, the first stripe microstructures310 e are disposed on the flat plate portion 316. In some examples, ablank region 330 is located on the tapered portion 314 (such as thelight guide plate 206 c shown in FIG. 6C) or on both of the taperedportion 314 and the flat plate portion 316 as shown in FIG. 15. Eachsecond stripe microstructure 312 e is a R-cut structure, i.e. across-sectional profile of each first stripe microstructure 310 e is inan arc-shape. Each microstructure 332 e is a R-cut structure, i.e. across-sectional profile of each microstructure 332 e is in an arc-shape.

According to the aforementioned embodiments of the present invention,advantages of the present invention are that a first microstructureregion of a light-emitting surface of a light guide plate near a lightincidence surface is set with various first stripe microstructures,which extend along a direction from one side of the main body near thelight-incident surface to the other side of the main body away from thelight-incident surface, so that the leakage light on the non-visibleregion near the light-incident surface is improved.

According to the aforementioned embodiments of the present invention,another advantage of the present invention is that a secondmicrostructure region of the light-emitting surface of the light guideplate following the first microstructure region is set with varioussecond stripe microstructures. Optical trends and degrees of lightconcentration of the light guide plate can be changed by varying shapes,angles, heights, depths or arrangements of second stripe microstructuresaccording to the gradient of each of the second stripe microstructures,preferably, sparser portions of the second stripe microstructures, whichare nearer the first microstructure region, can solve the problem of thebright bands of the light guide plate and improve the light-uniformity,and denser portions of the second stripe microstructures, which arefarther from the first microstructure region, can increase brightness ofthe light guide plate.

According to the aforementioned embodiments of the present invention,still another advantage of the present invention is that alight-incident surface is set with microstructures, so that theuniformity of the brightness distribution of the region near of thelight incidence surface is obviously improved, and hot spots can beeliminated.

As is understood by a person skilled in the art, the foregoing preferredembodiments of the present invention are illustrative of the presentinvention rather than limiting of the present invention. It is intendedto cover various modifications and similar arrangements included withinthe spirit and scope of the appended claims, the scope of which shouldbe accorded the broadest interpretation so as to encompass all suchmodifications and similar structure.

What is claimed is:
 1. A light guide plate, including: a main bodyincluding a light incidence surface, a light-emitting surface and alight reflective surface, wherein the light-emitting surface is oppositeto the light reflective surface, the light incidence surface isconnected between the light-emitting surface and the light reflectivesurface, and the light-emitting surface includes a first microstructureregion and a second microstructure region arranged in sequence, and thefirst microstructure region is nearer the light incidence surface thanthe second microstructure region; a plurality of first stripemicrostructures disposed in the first microstructure region andextending along a direction from one side of the main body near thelight-incident surface to the other side of the main body away from thelight-incident surface; and a plurality of second stripe microstructuresdisposed in the second microstructure region along the direction,wherein a gradient of each of the second stripe microstructures isgradually varied along the direction.
 2. The light guide plate accordingto claim 1, further including a plurality of microstructures disposed onthe light incidence surface.
 3. The light guide plate according to claim2, wherein a cross-sectional profile of each of the microstructures oreach of the first stripe microstructures is in a V-shape, an invertedV-shape or an arc-shape.
 4. The light guide plate according to claim 2,wherein each of the microstructures is a convex portion or a concaveportion.
 5. The light guide plate according to claim 1, wherein thelight-emitting surface further includes a blank region between the firstmicrostructure region and the light incidence surface.
 6. The lightguide plate according to claim 1, wherein the main body includes: atapered portion having a first end and a second end opposite to eachother, wherein a thickness of the first end is larger than a thicknessof the second end; and a flat plate portion extending from the secondend along the direction, wherein a thickness of the flat plate portionis equal to the thickness of the second end.
 7. The light guide plateaccording to claim 8, wherein the first stripe microstructures aredisposed on the flat plate portion.
 8. The light guide plate accordingto claim 6, wherein the light-emitting surface further includes a blankregion between the first microstructure region and the microstructures,and the blank region is located on the tapered portion or on both of thetapered portion and the flat plate portion.
 9. The light guide plateaccording to claim 1, wherein the first stripe microstructures areclosely adjacent to each other.
 10. The light guide plate according toclaim 1, wherein the first stripe microstructures are separated fromeach other
 11. The light guide plate according to claim 1, wherein eachof the first stripe microstructures is a convex portion or a concaveportion.
 12. The light guide plate according to claim 1, wherein each ofthe second stripe microstructures is a convex portion or a concaveportion.
 13. The light guide plate according to claim 12, wherein wheneach of the second stripe microstructures is the convex portion, thegradient of each of the second stripe microstructures includes a heightof each of the second stripe microstructures, and the height of each ofthe second stripe microstructures becomes gradually greater from thelight incidence surface along the direction; and when each of the secondstripe microstructures is the concave portion, the gradient of each ofthe second stripe microstructures includes a depth of each of the secondstripe microstructures, and the depth of each of the second stripemicrostructures becomes gradually greater from the light incidencesurface along the direction.
 14. The light guide plate according toclaim 13, wherein the gradient of each of the second stripemicrostructures further includes a width of each of the second stripe,microstructures, and width of each of the second stripe microstructuresbecomes gradually greater from the light incidence surface along thedirection.
 15. The light guide plate according to claim 12, wherein wheneach of the second stripe microstructures is the convex portion, thegradient of each of the second stripe microstructures includes a heightof each of the second stripe microstructures, and the height of each ofthe second stripe microstructures becomes gradually smaller from thelight incidence surface along the direction; and when each of the secondstripe microstructures is the concave portion, the gradient of each ofthe second stripe microstructures includes a depth of each of the secondstripe microstructures, and the depth of each of the second stripemicrostructures becomes gradually smaller from the light incidencesurface along the direction.
 16. The light guide plate according toclaim 15, wherein the gradient of each of the second stripemicrostructures further includes a width of each of the second stripemicrostructures, and width of each of the second stripe microstructuresbecomes gradually smaller from the light incidence surface along thedirection.
 17. The light guide plate according to claim 1, wherein across-sectional profile of each of the second stripe microstructures isin a V-shape, an inverted V-shape, an arc-shape or a trapezoid-shape.18. A light source module, including: a light guide plate as claimed inclaim 1; and a plurality of light sources adjacent to the lightincidence surface of he light guide plate.
 19. The light source moduleaccording to claim 18, wherein the light guide plate further includes aplurality of microstructures disposed on the light incidence surface.20. The light source module according to claim 18, wherein each of thesecond stripe microstructures is a convex portion or a concave portion;when each of the second stripe microstructures is the convex portion,the gradient of each of the second stripe microstructures includes aheight and a width of each of the second stripe microstructures, and theheight and the width of each of the second stripe microstructures becomegradually greater from the light incidence surface along the direction;and when each of the second stripe microstructures is the concaveportion, the gradient of each of the second stripe microstructuresincludes a depth and the width of each of the second stripemicrostructures, and the depth and the width of each of the secondstripe microstructures become gradually greater from the light incidencesurface along the direction.
 21. The light source module according toclaim 18, wherein each of the second stripe microstructures is a convexportion or a concave portion; when each of the second stripemicrostructures is the convex portion, the gradient of each of thesecond stripe microstructures includes a height and a width of each ofthe second stripe microstructures, and the height and the width of eachof the second stripe microstructures become gradually smaller from thelight incidence surface along the direction; and when each of the secondstripe microstructures is the concave portion, the gradient of each ofthe second stripe microstructures includes a depth and the width of eachof the second stripe microstructures, and the depth and the width ofeach of the second stripe microstructures become gradually smaller fromthe light incidence surface along the direction.